Even when a load capacity is greater than the output of a chopper, the load can be operated if a plurality of choppers are connected in parallel to the load. In this case, the load current needs to be equally shared among the plurality of choppers. Furthermore, it is necessary to connect a reactor between each chopper and the load, thereby suppressing influences of the timing of switching between choppers, and the difference between the output impedances (for example, see Japanese Patent Laying-Open No. 09-215322 (PTD 1) and Japanese Patent Laying-Open No. 2006-271102 (PTD 2)).